OBJECTIVETo detect the expression of Robo1 in lung cancer tissues, adjacent non-cancerous tissues as well as lung cancer brain metastasis, and explore the correlation of Robo1 expression to lung cancer brain metastasis.

METHODSSP (streptavidin-peroxidase) staining method was used to examine the Robo1 expression in specimens from 80 cases of NSCLC, 52 cases of adjacent non-cancerous tissues and 72 cases of lung cancer with single brain metastasis (without metastasis in other organs). The Robo1 expression was further examined in 17 self control cases with lung cancer tissues and their brain metastasis tissues. The results were assessed by Kaplan-Meier analysis and log-rank test.

RESULTSThe positive expression rate of Robo1 among adjacent non-cancerous tissues, lung cancers tissues and the lung cancer brain metastasis tissues were 1.9% (1/52), 13.8% (11/80) and 40.3% (29/72), respectively, and significant differences were detected among them (P < 0.05). During the 17 self control cases, the positive expression rate of Robo1 in lung cancer tissue and their brain metastasis tissues were 17.6% and 64.7%, respectively, with a significant difference between them (P < 0.01). Among the 72 cases of lung cancer brain metastasis, the median survival time of cases with positive Robo1 expression was 10 months, significantly shorter than that of cases with negative expression of Robo1 (17 months, P < 0.05).

CONCLUSIONSThe positive expression rate of Robo1 was increased in sequence from the lowest in adjacent non-cancerous tissues, intermediate in the lung cancer tissues to highest in the lung cancer brain metastasis tissues. The expression of Robo1 in lung cancer brain metastasis is negatively correlated with the prognosis of patients with lung cancer brain metastasis. Robo1 may promote the genesis and progression of lung cancer and lung cancer brain metastasis as a cancer-promoting oncogene.